Conventional art related to a gas circuit breaker for arc extinguishing by blowing arc-extinguishing gas to the arc generated between contacts when electric power is interrupted is disclosed in Japanese Patent Laying-Open No. 2002-203463 (PTL 1), for example. This publication of Japanese Patent Laying-Open No. 2002-203463 (PTL 1) discloses that one annular gap originating from an edge abutting against an electrically insulative cover member and having a wedge-shaped cross section which is open in the radial direction is formed between the abutting face and the insulative cover member, and that the edge is dielectrically shielded by an annular bead surrounding the abutting face.